body{
	margin: 0;
	padding: 0;
}
.box{
	width: calc(100vw - 30px);
	height: 200px;
	background: gold;
		.bordered();
	.box_item{
		width: 100px;
		height: 100px;
		background: #000;
		.bordered();
	}
}

.bordered {
  border-top: dotted 1px black;
  border-bottom: solid 2px black;
}